This is a work in progress, please email [email protected] if you have suggestions!
The purpose of this list is to give gardeners a heads up regarding plants that may cause problems for them down the road if they have space or time constraints, disabilities that limit ability to perform garden maintenance, neighbors or HOAs that may lodge complaints regarding native landscaping, and other similar reasons.
Plants are listed here for one of these reasons:
Spreads vigorously by vegetative growth (rhizomes, root suckers, stolons) or seeds when in their ideal conditions.
May draw complaints from neighbors or HOAs mainly due to appearance, such as being considered weeds despite being native or having conspicuously wind-dispersed seeds.
Has prickles, thorns, other chemical defenses, or sticky seeds.
Grows much larger or more quickly in typical garden conditions than many gardeners expect.
Forms thickets that can be difficult to control or remove later.
This doesn't mean these are "bad" plants. Many are keystone species in their native habitats and you should plant them if you can! For many plants, their ideal conditions are listed under their expandable note. Planting them outside of their ideal conditions may limit vigorous spread, but this should be considered experimental.
Tap or click any plant name to expand it and see notes. Tags show at-a-glance what to watch for — tap any tag for a fuller description.
Trees and shrubs
Acer macrophyllumbigleaf maple
Drops large amounts of plant matter including branches and trunks. Produces many winged, wind-dispersed seeds called samaras that germinate readily.
Alnus rubrared alder
Produces prolific amounts of wind-dispersed seeds with a high germination rate and seedlings that grow rapidly. Most aggressive on moist, disturbed soils.
Berberis aquifoliumTall oregon grape
Spreads by rhizomes and bird-dispersed seeds under ideal conditions, especially moist soils in part-shade. Prickly and can encroach into walkways and driveways if not pruned.
Berberis nervosaCascade oregon grape
Spreads by rhizomes and bird-dispersed seeds under ideal conditions, especially moist soils rich in organic matter. Prickly and can encroach into walkways and driveways if not pruned.
Cornus sericeaRed-twig dogwood
Spreads by stolons and bird-dispersed seeds under ideal conditions, especially wet to seasonally wet soils and streambanks.
Corylus cornuta var. californicabeaked hazel
Produces suckers. Animals bury the nuts in random locations where they often sprout. Most aggressive in rich, moist forest edge soils. Resprouts from stumps readily and can be difficult to remove.
Crataegus douglasiiDouglas' hawthorn
Produces bird-dispersed seeds and root suckers that form thorny thickets. Most aggressive in moist soils.
Gaultheria shallonsalal
Can spread by runners under ideal conditions, especially loose, moist soils with lots of organic matter.
Malus fuscapacific crabapple
Produces suckers, sprouts from bird-dispersed seeds. Can be messy. Most aggressive in wet ground or floodplains.
Oemleria cerasiformisosoberry
Can grow into a thicket from basal sprouts if not controlled. Produces many seedlings when pollination occurs. Most aggressive in partly-shaded moist soils.
Oplopanax horridusdevil's club
Forms rhizomatous colonies in moist to wet shade. Very thorny.
Physocarpus capitatuspacific ninebark
Spreads by root suckers, self-layering, and prolific seed production especially in moist soils.
Populus trichocarpablack cottonwood
Spreads by root suckers and conspicuously wind-dispersed seeds. Known for frequently dropping large branches and trunks. Most aggressive in wet ground and floodplains.
Prunus emarginatabitter cherry
Spreads profusely by suckers and seeds under ideal conditions, especially disturbed areas.
Prunus virginiana var. demissachokecherry
Spreads profusely by suckers and bird-dispersed seeds under ideal conditions, especially with moderate moisture.
Rosa nutkanaNootka rose
Spreads vigorously by root suckers under ideal conditions, especially full sun with moderate moisture.
Rosa pisocarpaclustered rose
Spreads vigorously by root suckers under ideal conditions, especially moist to wet soils.
Rubus leucodermisblackcap raspberry
Spreads by root suckers and by rooting at stem tips. Creates unwieldy thickets if not pruned regularly.
Rubus parviflorusthimbleberry
Spreads vigorously by rhizomes under ideal conditions, especially moist part-shade.
Rubus spectabilissalmonberry
Spreads vigorously by rhizomes under ideal conditions, especially moist to wet soils in shade to part-shade.
Rubus ursinustrailing blackberry
Its horizontal vine-like stems grow vigorously, root at the tips, and can be a tripping hazard. Will intrude into neighbors’ yards. Difficult to remove once established.
Salix geyerianaGeyer's willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in wet soils.
Salix hookerianaPiper's willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in wet soils.
Salix lasiandraPacific willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in wet soils.
Salix lasiolepisArroyo willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in wet soils.
Salix scoulerianaScouler's willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in moist to wet soils.
Salix sessilifoliaSoft-leaved willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in wet soils and streambanks.
Salix sitchensissitka willow
Spreads by root suckers and conspicuously wind-dispersed seeds. Most aggressive in wet soils.
Sambucus ceruleablue elderberry
Grows large rapidly under ideal conditions and produces suckers. Frequently drops branches.
Sambucus racemosared elderberry
Grows large rapidly under ideal conditions and produces suckers. Frequently drops branches.
Spiraea douglasiihardhack
Spreads by rhizomes under ideal conditions, especially seasonally wet to wet soils.
Symphoricarpos albussnowberry
Spreads vigorously by rhizomes under ideal conditions, especially moist, rich soils in sun to part sun.
Vines
Clematis ligusticifoliawestern clematis
Vigorous climber. Can smother shrubs and grow into neighbor’s yards.
Lonicera ciliosaorange honeysuckle
Vigorous climber. Can smother shrubs and grow into neighbor’s yards.
Lonicera hispidulapink honeysuckle
Vigorous climber. Can smother shrubs and grow into neighbor’s yards.
Ferns
Athyrium filix-feminaLady fern
Spreads vigorously by short rhizomes and spores under ideal conditions, especially moist part-shade.
Equisetum arvensefield horsetail
Spreads vigorously by deep underground rhizomes. Difficult to remove once established. Most aggressive in moist, disturbed soils.
Equisetum hyemalescouring rush
Spreads vigorously by deep underground rhizomes. Difficult to remove once established. Most aggressive in moist to wet soils.
Equisetum laevigatumsmooth scouring rush
Spreads vigorously by deep underground rhizomes. Difficult to remove once established. Most aggressive in moist to wet soils.
Pteridium aquilinumbracken fern
Spreads by deep horizontal rhizomes. Allelopathic, meaning it inhibits the growth of other plants. Difficult to remove once established.
Forbs
Note: most native annuals have the potential to spread vigorously by seed under the right conditions even if not listed here.
Allium cernuumnodding onion
Can spread by offsets and seed itself vigorously under ideal conditions, especially moist, well-drained soils in full to part sun.
Anaphalis margaritaceapearly everlasting
Spreads vigorously by rhizomes, especially in full sun. Not kept in check by dry conditions.
Apocynum cannabinumhemp dogbane
Spreads vigorously by rhizomes and conspicuously wind-dispersed seeds. Most aggressive in full sun with moist to wet soils.
Artemisia douglasianaDouglas' sagewort
Spreads vigorously by rhizomes to 5+ feet wide under ideal conditions, especially moist soils.
Asclepias speciosashowy milkweed
Spreads vigorously by rhizomes and conspicuously wind-dispersed seeds in sunny spots.
Bidens cernuanodding sticktight
Seeds attach themselves tenaciously to clothing and animals and are difficult to remove. Can grow vigorously from seed, especially in moist to wet areas.
Bidens frondosaleafy sticktight
Seeds attach themselves tenaciously to clothing and animals and are difficult to remove. Can grow vigorously from seed, especially in moist to wet areas.
Bidens vulgatatall sticktight
Seeds attach themselves tenaciously to clothing and animals and are difficult to remove. Can grow vigorously from seed, especially in moist to wet areas.
Chamaenerion angustifoliumfireweed
Spreads vigorously by rhizomes under ideal conditions, especially sunny, disturbed areas. Conspicuously wind-dispersed seeds.
Cirsium brevistylumShort-style thistle
Neighbors and HOAs will not be able to distinguish it from invasive thistles. Conspicuously wind-dispersed seeds.
Cirsium eduleedible thistle
Neighbors and HOAs will not be able to distinguish it from invasive thistles. Conspicuously wind-dispersed seeds.
Claytonia perfoliataminer's lettuce
Seeds itself around vigorously under ideal conditions. Considered a weed by some despite being native.
Claytonia sibiricacandyflower
Seeds itself around vigorously under ideal conditions. Can be mistaken for miner’s lettuce, which some people consider a weed.
Collomia grandifloraGrand collomia
Vigorous seeder, can spread throughout sunny spots and often requires thinning.
Elymus glaucusblue wildrye
Grows by short rhizomes and seeds vigorously.
Epilobium ciliatumfringed willowherb
Seeds itself around vigorously, including in containers. Conspicuously wind-dispersed. Considered a weed by many despite being native.
Erythranthe guttatayellow monkeyflower
Produces copious amounts of seed that germinate readily under ideal conditions including in containers and can spread by stolons. Most aggressive in wet soils and seepage areas.
Eschscholzia californicaCalifornia poppy
Vigorous seeder, especially in disturbed soil in full to part sun. Note that most California poppy seeds available on the market are not the native ecotype and are likely to be cultivars or hybrids.
Galium aparinecleavers
All parts of the plant stick to clothes and animals including the seeds. Can grow over other plants and smother them early in the season, but easy to remove. Considered a weed by many despite being native.
Geum macrophyllumLarge-leaved avens
Seeds itself around vigorously under ideal conditions, especially moist part-shade. Can crowd out other plants. Barbed seeds stick to clothing and animals. Neighbors and HOAs will not be able to distinguish it from invasive Geum urbanum.
Heracleum maximumcow parsnip
Its sap causes skin reactions including photodermatitis. Neighbors will not be able to distinguish it from invasive plants in the genus Heracleum.
Lupinus rivularisriverbank lupine
Seeds itself vigorously under ideal conditions, especially moist disturbed or gravelly soils in sun.
Maianthemum dilatatumfalse lily of the valley
Spreads vigorously by rhizomes, especially in moist to wet shade or part shade.
Mentha canadensiswild mint
Spreads vigorously by rhizomes under ideal conditions, especially moist to wet soils.
Microseris laciniatacutleaf microseris
Neighbors and HOAs will assume the flowers are dandelions. Conspicuously wind-dispersed seeds.
Petasites frigiduscoltsfoot
Spreads vigorously by rhizomes under ideal conditions, especially moist to wet soils.
Phacelia nemoralisshade phacelia
Seeds itself around vigorously under ideal conditions, especially on moist soils in part shade. Can intrude on neighboring plants.
Prunella vulgaris var. lanceolatalanceleaf self-heal
Seeds itself around vigorously and can spread by stolons under ideal conditions, especially moist, disturbed ground and lawns. Can crowd out other plants. Neighbors and HOAs will not be able to distinguish it from non-native Prunella vulgaris var. vulgaris.
Ranunculus occidentalisWestern buttercup
Seeds itself vigorously under ideal conditions, especially partly-shaded moist and disturbed soils. Neighbors will confuse it with invasive Ranunculus repens.
Solidago canadensis
OregonFlora considers Solidago canadensis to be a synonym for both Solidago elongata and Solidago lepida. Solidago canadensis from other locations may not be the same species, i.e. not native to Oregon.
Solidago elongataWest Coast goldenrod
Spreads vigorously by rhizomes under ideal conditions, especially moist soils with sun. Neighbors may blame it for allergies due to confusion with ragweed, even though goldenrod is not wind pollinated and unlikely to cause seasonal allergies.
Solidago giganteagiant goldenrod
Spreads vigorously by rhizomes under ideal conditions, especially moist to wet soils with sun. Neighbors may blame it for allergies due to confusion with ragweed, even though goldenrod is not wind pollinated and unlikely to cause seasonal allergies.
Solidago lepidawestern goldenrod
Spreads vigorously by rhizomes under ideal conditions, especially moist soils with sun. Neighbors may blame it for allergies due to confusion with ragweed, even though goldenrod is not wind pollinated and unlikely to cause seasonal allergies.
Solidago missouriensisMissouri goldenrod
Spreads vigorously by rhizomes under ideal conditions, especially dry, open areas. Neighbors may blame it for allergies due to confusion with ragweed, even though goldenrod is not wind pollinated and unlikely to cause seasonal allergies.
Stachys cooleyaeCooley's hedgenettle
Spreads vigorously by rhizomes under ideal conditions, especially moist to wet soils in part shade.
Symphyotrichum subspicatumDouglas' aster
Spreads vigorously by rhizomes under ideal conditions, especially moist soils with full to part sun.
Urtica dioica ssp. gracilisstinging nettle
Can cause a painful or unpleasant sensation and rash on contact. Can spread vigorously by rhizomes under ideal conditions, especially moist soils.
Graminoids
Note: most native graminoids (which includes grasses, sedges, and rushes) have the potential to spread vigorously by seed under the right conditions even if not listed here. Neighbors may complain about grasses allowed to grow tall or go to seed even if native.
Calamagrostis canadensisbluejoint reedgrass
Spreads aggressively via rhizomes in moist to wet soils.
Carex obnuptaslough sedge
Spreads aggressively via rhizomes in moist to saturated soils.
Schoenoplectus tabernaemontanisoftstem bulrush
Spreads aggressively via rhizomes in saturated soils and standing water.
Scirpus microcarpusSmall-fruited bulrush
Spreads aggressively via rhizomes and seeds in wet soils and pond margins.
Typha latifoliacattail
Spreads aggressively via rhizomes and wind-dispersed seeds in saturated soils and standing water.